Center for copying lathes



`1?@11111, 1947. G, P s, CROSS 2,415,465

CENTER FOR COPYING LATHESl Filed April 6, 1944 l By itomey 4 Patented Feb. 11, 1947 IUNTTED STATES PATENT oEFlcE CENTER FOR COPYING LATHES Garrett P. S. Cross, Beverly, Mass., assignor to United Shoe Machinery Corporation, Flemington, N. J., a corporation of New Jersey Application April 6, 1944, Serial No. 529,775

7 Claims.

This invention is concerned with a problem involved in the manufacture of two-part lasts. The problem arises in consequence of girth grading in a copying lathe, regardless of whether the generated product is an individual forepart of a two-part last or a last in which the forepart and heel part are integral, but the present invention is not concerned with lastsof the latter type.

The problem under consideration is due to the fact that girth grading in a copying lathe unavoidably alters the toe spring of a last. Specically, the toe spring is increased by grading up and decreased by grading down, but in the case of grading the forepart of a two-part last, it is possible to counteract the effect of grading on the toe spring by regulating the angular relation of the joint surface of the block and the turning axis thereof in the process of setting up the block in a copying lathe. This does not alter the shape of the generated forepart nor its position in space during the turning operation, but it does alter the length of the bottom of the forepart, and later, when the generated forepart is finally assembled with a heel part, the abutting portions of their joint surfaces below the hinge become effective to determine the quantity of toe spring.

As herein exemplied, the invention is ernbodied in a copying lathe of the type disclosed in United States Letters Patent No. 2,072,228, granted March 2, 1937, on 'application of Topham et al. modified by the substitution of improved means for holding a forepart block, the turning center for holding the toe end of the block being provided with adjustable means arranged to locate that end of the block in any one of a variety of positions differently related to the turning axis of the lathe.

The utility of a turning center such as that mentioned above is predicated upon a known practice of preparing a forepart block for turning by forming its joint surface at the butt end and boring a locating socket in its toe end with thev aid of a jig to insure a standardized relation of one to the other. Examples of jigs designed for such use are disclosed in United States Letters Patent No. 1,969,739 and No. 2,030,141 both granted to J. Fitzpatrick. The locating socket bored in the toe end of the block is intended to establish the turning axis of the block and in some cases to receive a turning center of a lathe. Its utility in that respect is predicated upon placing it exactly in a standardized relation to the joint surface at the opposite end of the block to insure a correct set-up of the block with regard to the turning axis of the lathe.y The ex- .A

2 pression .standardized relation means that relation which is standard for a true copy generated at zero grade.

The adjustable means of the present improved turning center includes a tongue the tip of which is formed and arranged to occupy the locating socket prior to forcingthe center into the block. The tongue may be adjusted to place the socket in concentric relation to the turning axis or in various eccentric relations thereto, and if the adjustments be coordinated with the adjustments of the girth-grading mechanism the graded lasts will have approximately the same toe spring as a non-graded last.

The invention also provides a complemental feature in the head stock of the lathe, namely, a chuck designed to hold the butt end of a forepart block solely-by engagement with a cylindrical surface of the hinge portion of the block. The entire block-engaging surface of 'the chuck herein illustrated is also cylindrical and conforms to the corresponding surface of the block except in angular extent, the concave surface of one of the elements having slightly less angular extent than the convex surface of the other element to provide clearance for relative angular adjustment commensurate with the adjusting requirements at the toe end of the block. A chuck embodying the feature above described will serve the purpose in View when grading up or down as Well as when the girth-grading mechanism is set for Zero grade.

Referring to the drawing,

Fig. 1 is a front elevation of a portion of a copying lathe embodying the present invention;

Fig. 2 is an enlargement of the forepart block, the head stock chuck, and a portion of the toe center as they appear in Fig. 1;

Fig. 3 represents the outlines of tWo lasts, one generated at zero grade in full lines and the other graded up girthwise;

Fig. 4 is a sectional view of the toe center ini eluded in Fig. 1 at the right thereof; and

Fig. 5 is a cross section indicated by line V-V of Fig. 4.

A discussion of Figs. 2 and 3 will reveal the problem under consideration and the manner in designed to insure a. standardized relation be tween the socket and the joint surface.

The joint surface illustrated herein includes a cylindrical hinge surface I3 and two stop faces I4 and I5 located respectively above and below the hinge surface. The stop face I5 is the one to be particularly considered, since its coaction With a corresponding stop face I6 of a heel part II determines the amount of toe spring of a last when the parts are assembled as represented in Fig. 3.

The head stock represented in Figs. 1 and 2 includes a live spindle I8, a face plate I9 carried thereby, and a chuck affixed to the faceplate. The chuck is provided with a cylindrical' sur.;

face 2l of the same radius as the hinge surface I3 of the block and of sucient circumferential extent to rotate the block about the turning axis X-X In some circumstances the forepart Will be provided with aiconcave hinge surface and its mated heel part will be provided with a convex hinge' surface. In such circumstances the chuck 2i) will be replaced by one having a convex cylindrical surface instead of a concave surface 2l. In either case, the chuck will be del signed to provide clearance gaps between itself and the faces I4 and I5 of the block.

Assuming that a block H is set up in' a lathe with its socket I2 in concentric relation with the turning axis, and assuming` also that a forepart of the style indicated isv to be generated at zero grade, the distance Y from its turning axis to the ball surface will be equal to the cor responding distance in the model 22 (Fig. 1). If the forepart were graded up girthwise; this distance would be greater, but if graded down, it would be less, and the amount of toe spring Would be altered accordingly because the relation of thetoe end to the turning axis would not be affected by the' grading factor.

One possible expedient by which' the toe spring of an up-graded forepart could be reduced to counteract the effect of the grading. factor would be to trim a thin layer of` stock frornthe stop face I5, thereby permitting the turning axis of the forepart to take the position indicated by lineA X'-X (Fig. 3)' instead of its true position. indicated by line X-X. On the other hand, if the toe spring were reduced by grading down, it could be increased by attaching a thin layer of wood to the face l5, but these expedientswould be unsatisfactory for obvious reasons. Nevertheless, almost theA same results can be obtained without trimming. or patching by setting the socket I2 above the turning axis whenY which these faces would lie during' the turning operation if the socket l2 were placed above the turning axis. As to the face is, its change of' location would havethe ultimate effect of lowering the toe end of the forepart with respect toY an assembled heel part and thereby reducing the amount of toe spring. Thus, `a forepart gradedv up (dotted lines in Fig. 3) can be turned in a Way to counteract an increase in toe spr'ir'igduetothe grading factor. On the other' hand; a

reduced toe spring produced by grading down may be corrected during the turning operation by placing the socket I2 below the turning axis. This would shift the stop face I5 slightly away from the toe end of the forepart and result in raising the toe end with respect to the heel part when the stop faces I5 and I6 abut each other.

The lathe represented in the drawingl is provided with means for obtaining the results above described. A tail stock center 25 in concentric relation to the turning axis of the spindle I8 isy arranged to cooperate with the chuck 20 to support a block II. A tubular portion of the center is provided with a chamber 26 having an open mouth defined by a sharp work-indenting edge 21. The shank 28 of the center is affixed to a driven gear 29. An adjustable tongue 30 is nested in the chamber 2B, but its tip 3I projects through and beyond the mouth of the latter to enter a socket I2 in the toe end of a block II. The tip SI is spherical and its diameter is the same as that of the drill used to bore the socket. The inner end 32 of the tongue is also spherical, likewise an intermediate portion 33l which serves as a fulcrum and has a bearing in a cylindrical internal surface that forms the chamber 26,

An adjustable thrust member 34, cylindrical in form, is installed in a bore intersecting the chamber 26 and lying on an axis at right angles to the turning axis. The inner end of the member 3Q engages the ball end 32 of the tongue, their contact being maintainedv by a spring follower 35 also engaging the ball end. The' members 34' and 35 are encircled and confined by a' collar 3SV capable of being rotated manually with respect to the vcenter 25. The internal surface of this collar is a cam surface including concentric segments and a series of vthree depressions 3l, 38 and 39 of graduated depths. The center is provided with screws Mifor' retaining the collar without binding it.

When the depression 38 of intermediate depth is in register with the thrust member 34, it will maintain the tip end 3I of the tongue in concentric relation t'o the turning axis, and this is the adjustment that would normally be made when a forepart is to be turned at zero grade. The shallower depression 3l will locate the tip end3\I at one side ofv the turning axis (Fig. 4), butl the deeper depression 39 will locate it at the opposite side. As a matter of convenience,A the depressions 3'IY and 39may be'made to correspond to-onevWidth-grade'above or below zero grade; as the case may be.

In accordance withnthe lathe organization' more fully shown and described in" the aforesaid-f LettersvPatent No; 2,0'723228,` ther elements hereinbefore described arerall'carried by a' swing frame? comprising arms MJ; 4I and E2 and aj pivot'shaft 43 of squarelsection between its ends. The arm 4B' provides? bearings for Ithe' live` spindle I8 and carries gearing'lll for driving'it. The/arms 4I and 2 are' jtli adjustable OWad alll f-IOl llll`ftl`lll dil; one having bearings for a tail stock center fonsupp'o'rting the toe end' of the modelarid thei other having bearings for the ycenter 25v which carries the toe end of theY block I'I. These bear-y ings all remain on a commonI turning axis X`-X. A face plate Alliiaflixed to the spindle I8 supports' and drives the butt'end of the model 22. A transmissiorrshaft'l 47 journaled in the arms IIil,` 4I andv AZdrives the spindle I'8 and bo'tli tail stock centers in synchronism; the gear' train 48 serving ther" center 45 as another train including the gear 29 serves `the center 25.

When setting up a block ll in the lathe, the operator will rst adjust the collar 36, if need be, according to whether a forepart is to be graded up or down or turned at Zero grade. The arm d2 and the center 25 may be shifted toward the chuck by turning the screw rod 49 the thread of which engages an internal .thread in the arm 42. Once the socket I2 in the block has been placed in register with the tip 3| of the locating tongue the arm 42 may be advanced to drive the indenting end 21 of the center into the block, the tongue then being eiectiveto maintain the socket in the desired relation to the turning axis during the indenting stage.

Having described my invention, what I claim as new and desire to secure by Letters Patent o-f the United States is:

1. In a lathe of the copying type in which bearings for a live spindle and a tail stock center are maintained in coaxial relation, a rotatable tail stock center having work-indenting means, a radially adjustable work-locating tongue carried thereby, the tip of said tongue projecting beyond said indenting means to occupy a socket in a work piece, and means carried by the center and associated with said tongue for shifting said tip radially to and from the axis of the center.

2. A lathe comprising a rotary turning center and means for driving it, the center having a Work-supporting portion at one end and a chamber forming an open mouth in said end and surrounding its turning axis, a work-locating tongue carried by the center and nested in said chamber, the tip of said tongue projecting through said mouth and beyond said work-supporting portion, and means associated with the tongue for shifting its tip radially .toward and from the turning axis of the center.

3. A rotatable lathe center having a work-supporting portion at one end and a chamber forming an open mouth in said end, a work-locating tongue nested in said chamber, the tip of said tongue projecting through said mouth and beyond said Work-supporting portion, and means associated with said tongue to maintain its worklocating tip in various positions of adjustment radially of the turning axis of the center.

4. A tubular rotatable lathe center having a sharp work-indenting edge for supporting one end of a work piece, an angularly adjustable tongue nested in the center and having a bearing therein, the tongue having a work-locating tip projecting beyond said edge, and adjusting means associated with said tongue for shifting its worklocating tip to and from the turning axis of the center.

5. A tubular rotatable lathe center having an internal cylindrical surface and anopen mouth defined by a sharp work-indenting edge, an angularly adjustable tongue nested in the center and having a spherical fulcrum portion engaging said cylindrical surface, the tongue also having a work-locating tip projecting beyond said edge, and adjusting means associatedwith said tongue for shifting said tip to and from the turning axis of the center.

6. A lathe center as defined in claim 4 in which the adjusting means comprises a manually rotatable collar surrounding the center and having a bearing thereon, said collar having an internalv cam surface, a thrust member between said cam surface and the tongue, and resilient means acting on the tongue in opposition to said thrust member.

7. A lathe center as defined in claim 4 in which the adjusting means comprises a manually rotat- -able collar surrounding the center and having a bearing thereon, the collar having a series of depressions of diicrent depths in its internal surface, a thrust member between said surface and the tongue, and resilient means acting on the tongue in opposition to said thrust member.

- GARRETT P. S.. CROSS.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 2,072,228 Tophein et al Mar. 2, 1937 2,333,055 Terrell Oct. 26, 1943 1,069,797 Lyons Aug. 12, 1913 842,478 Loewer Jan. 29, 1907 1,860,723 Ryan May 21, 1932 1,969,738 Fitzpatrick Aug. 14, 1934 1,319,585 Hunt Oct, 21, 1919 809,353 Zange Jan. 9, 1906 2,142,639 Fish Jan. 3, 1939 2,247,721 Wright July 1, 1941 

